two's complement help

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two's complement help

calccrypto 17 Jan 2010 05:46

when a pseudocode/directions says to do "two's complement addition of [units. in my case, 32 bit values called 'words'] ", what do you do? do you change both values and then add them? change 1 value and add/subtract? add them, mod 2^32 and then change them? add, change and discard the extra bits? what??

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Re: two's complement addition for 2 postive numbers

calccrypto 17 Feb 2010 03:31

can someone please tell me? this is getting ridiculous. people have a tendency to not answer me except for their own benefit. a lot of times, im lucky if i get insults for responses

its not like i havent searched for info, but either people tell me to shut it, are really vague, or dont give me anything. google hasnt given me anything. wikipedia doesnt say anything about when both numbers are positive except that the example they give is wrong

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Last edited on 17 Feb 2010 03:46 by calccrypto Show more

Re: two's complement help

normfather 15 Feb 2023 00:59

Still does not appear to be a good way to do it. A way to do though on the TI Nspire is as follows:

Take the MSB of the first number (if 0 can skip), enter -(2 to the power of that digits index). Add it to the rest of the binary number after removing the MSB from that number (Ex: -1446 + 0b1101110101). The calculator will give you the result as a decimal number (base 10).

Do the same for the other one and add. Hope this helps someone who may have the same query.